| About this Abstract |
| Meeting |
TMS Specialty Congress 2024
|
| Symposium
|
Accelerating Discovery for Mechanical Behavior of Materials 2024
|
| Presentation Title |
Coupling Effects of Grain Size and Dislocation Density on Stress-induced Martensitic Transformation of Nanocrystalline NiTi Alloys: A Molecular Dynamics Study |
| Author(s) |
Zhihao Zhao |
| On-Site Speaker (Planned) |
Zhihao Zhao |
| Abstract Scope |
In this work, the coupling effects of grain size (GS: 5 nm−30 nm) and dislocation density (0−1 E16 m-2) on stress-induced martensitic transformation (MT) of nanocrystalline NiTi alloys were investigated quantitatively by molecular dynamics (MD) simulation. The forward transformation stress decreases with the increase of GS and dislocation density, which is attributed to the fact that the energy barrier of martensitic nucleation decreases with GS and dislocation density. The sensitivity of transformation stress to dislocation density increases with the increase of GS. We found that residual strain decreases with the GS but increases with dislocation density. The origins of residual strain are decoupled into (i) plastic deformation of grain boundaries and the disordered structure caused by dislocations, and (ii) the residual martensite. Plastic deformation is the main source of residual strain, except when residual martensite accumulates significantly (e.g., GS = 30 nm and dislocation density = 1 E16 m-2). |
| Proceedings Inclusion? |
Definite: Other |